Fluid-operated hammer



April 23, 1963 E. v. NIELSEN FLUID-OPERATED HAMMER 2 Sheets-Sheet 1r/flw //7/// Filed June 24, 1959 4 INVENTOR Edward 1,7615? BY Q M km

ATTORNEYS April 23, 1963 E. v. NIELSEN- 3,036,501

i FLUID-OPERATED HAMMER Filed June 24, 1959 t 5 52 If 45 56 2Sheets-Sheet 2 uum I INVENTOR BY a ATTORNEYS United States Patent C)3,086,501 FLUID-OPERATED HAMMER Edward V. Nielsen, Darien, Conn,assignor to Henry E. Kyburg, Bridgeport, Conn. Filed June 24, 1959, Ser.No. 822,567 Claims. (Cl. 121-21) is provided with a valve assemblyhaving a movable valve disk therein which is adapted to be sequentiallyshifted between hammer driving and cocking positions so that fluidemanating from a source of fluid under pressure may reciprocate thehammer or piston. The valve disk is sequentially shifted in response tothe position of the harn- -rner in the barrel causing a reversal of apressure differential which is created between opposite sides of thevalve disk, so that fiuid emanating from a source offluid under pressuremay be directed first against one side of the reciprocable hammer andthereafter against the other side for reciprocating the same. Thesequential shifting of the valve disk is accomplished by communicatingthe interior of the barrel with opposite sides of the valve disk andproviding means for opening or closing off such communication toincrease or decrease the fluid pressure at opposite sides of the disk,as required.

A feature of the invention is the provision of an adjustable triggerassembly or control means for accurately regulating the flow of fluidunder pressure to the valve assembly so that the rapidity of the hammerstroke and the force of the blow may be controlled. While adjustabletrigger assemblies have been known prior to the instant invention, thepresent trigger assembly is novel in that the valve thereof may beaccurately adjusted to deliver just the required amount of fluid to thevalve assembly and is locked in adjusted position by resilient lockingmeans.

The resilient locking means prevent the trigger assembly from losing thedesired adjustment as the result of vibration and shock, etc., yetenable an operator to readjust the assembly without ditficultmanipulation of the parts or having to resort to the use of tools or thelike.

Another feature of the invention resides in the improved tool mountingmeans, which is adapted to support known each of these require thereconstruction of the tool which is being operated by the hammer, orcreate problems in the mounting and removal of the tool in and from thehammer. The present mounting means comprises a supporting member in theform of a sleeve, adapted to slidably support the tool, connected to thebarrel and cooperating with the barrel to house resilient means fornormally biasing the tool away from hammer contacting position. Thesleeve or support for the tool is provided with resilient means forgripping the tool when it is inserted therein for maintaining it insupported position, .the resilient nature of the tool gripping meansbeing adapted to facilitate the removal and insertion of the tool.

It is, therefore, .also an object ofthe invention to pro- 3,086,501Patented Apr. 23, 1963 .vide a fluid-operated hammer in which thedriving and cocking operation of the hammer or piston is a function of asequentially actuated valve assembly, thereby eliminating the usualextraneous cocking or return device, such .as springs or the like.

.Another object of the inventionis to provide a fluidoperlated hammerhaving a self-contained, self-locking, readily adjustable controlmechanism .or trigger assembly for regulating the fiowof fluid to thevalve assembly whereby any desired rate of reciprocation or force ofhammerblow maybe obtained.

Still'another object of the invention is to provide a fluid-operatedhammer having means for mounting a. tool in alignment .with thereciprocating hammer thereof which normally .biasesthe tool away. fromhammer contacting position, so that the hammer may idle without dangerwhen the tool is not engaged with a workpieceand which is adapted tofacilitate the mounting and. removal of the .tool in association withthe hammer.

A further object of the invention is to provide a .fluid- .operatedhammer wherein the shock of hammer reciprocation is substantiallyabsorbed and in which 'the air discharged' frorn the .barrel as thehammer reciprocates, is utilized to cool .and clean the work and end ofthe Working tool.

It is still further an object of the invention to provide afluid-operated hammer which is simple in structure, readily assembledand disassembled for cleaning andrepairand of such rugged character itwill function over long periods of .timeWith. freedom from alldifficulties.

Other objects and advantages of the invention will be apparent from thespecification and claims when considered in connection with the attachedsheets of drawings, illustrating one form of the invention, wherein likecharactersrepresent like parts and in which:

FIGURE '1 is a side elevational view, in section, taken in thedirectionofthe arrows 1-1 in FIG. 2, showing a fluid-operated hammerembodying the concepts of the invention;

FIG. 2. is a fragmentary cross-sectional view taken in the direction ofthe arrows 2-2 in FIG. 1;'

FIG. 3 is a fragmentary cross-sectional view taken in the direction ofthe arrows 33 in FIG. 1;

FIG. 4 is a fragmentary sectional view taken in the direction of thearrows 4-4 in FIG. 1;

FIG. 5 is a fragmentary cross-sectional view taken in the direction ofthe arrows '5-.-5 of FIG. 1;

FIG. 6 is an enlarged fragmentary view, in section, of

.the trigger assembly shown in FIG. 1;

FIG. 7 is a fragmentary cross-sectional view taken in thedirection ofthe arrows 77 in FIG. 6; and

FIG. 8 is a fragmentary view, in section, of the tool mounting means ofFIG. 1.

,Referring now to the drawings, a fluid-operated hammer 10' is shownembodying the concepts of the invention. While it willbe understood thatthe hammer 10 may be either operated by a liquid or gas under pressure,in the illustrated form of the invention, for purposes of explanation,an air-operated hammer is described.

.The air hammer 10 comprises a housing llhaving a valve assembly 12therein. The housing 1 1, according to conventional practice, includes apistol grip 13, to facilitate the handling of the, air hammer, and anintegral valve assembly mounting portion 14. The valve assembly mountingportion 14, which is substantially cylindrical in cross-section, isclosed at one end and provided at the other end with an open threadedmouth 15 adapted to .tool mounting assembly 18 for supporting a tool 19'in operating alignment with the hammer 17. The housing 11 is providedwith means 20, in the form of a screw threaded coupling 21 and conduit22, for connecting the housing to a source of fluid, such as air, underpressure (not shown) and for transmitting the fluid to the valveassembly 12. Mounted in pistol grip 13 of housing 11 and dissectingconduit 22 between the source of air under pressure and the valveassembly, is a trigger assembly 23 adapted to control the flow of air tothe valve assembly.

The valve assembly 12, which holds a movable valve disk 24 and includesa pair of complementary valve housing members 25 and 26, is removablymounted in valve assembly mounting portion 14 on a shoulder 27 formedtherein in alignment with the bore 28 of barrel 16. Pins 29 extendingthrough complementary bores in housing members 25 and 26 retain themembers in aligned assembled position and further pins 30 adapted to bereceived in bores 31 of barrel 16 align the valve assembly with thebarrel and maintain it against movement relative thereto in theassembled air hammer.

The valve housing members 25 and 26 form between them a central pocket32 which is adapted to loosely house the movable valve disk 24 so thatit may be shifted from side to side therein, for a purpose to behereinafter more fully explained. The valve housing members are formedwith a plurality of passages therein communicating with the pocket 32and opposite sides of valve disk 24 for sequentially transmitting theoperating fluid, in the present illustration air, first to one side ofthe disk and then to the other so that the disk is shifted to enable thefluid to reciprocate the hammer. The valve housing member 26 is providedwith a pair of passages 33 communicating with pocket 32 at one side ofthe valve disk and with an annular passage 34 that is in opencommunication with conduit 22 from the source of air under pressure. Acentral bore 35 in member 26 opens pocket 32 to the bore 28 of barrel16. Valve housing member 25 is provided with passages 36, similar topassages 33 but communicating with pocket 32 at the opposite side of thevalve disk. The passages 36 communicate with annular passage 34 throughpassages 33, in member 26, and lateral passages 36a. Additionally, themember 25 is formed with passages 37 communicating with pocket 32 andwith a compression chamber 38 formed in barrel 16 at the end directedaway from valve assembly 12. The passages 37 are connected to thecompression chamber through conduits 39 extending longitudinally ofbarrel 16.

The barrel or reciprocable piston cylinder 16 is formed with a pair oftransverse vent openings 40 and 41 for communicating the bore 28 withthe atmosphere and is provided with threads on its outer surface wherebya hood or vent shield 42 may be secured thereover. In the illustratedform of the invention, the hood 42 is secured to barrel 16 adjacenthousing portion 14 and engages an extension of the threads which connectthe barrel to the housing.

In the operation of air hammer 10, assuming at the start that hammer orpiston 17 is in driving or tool contacting position as shown in FIG. 1,air under pressure is transmitted through conduit 22 to valve assembly12. In the illustrated position of the hammer 17, valve disk 24 ispositioned in pocket 32 to valve-off barrel 16 and passages 33 from thepocket. The position of the valve disk is the result of a pressurediflerential created between the opposite sides thereof. The barrel sideof the valve disk is under less pressure than its opposite side becausethe bore 28 of the barrel and the bore 35 of valve housing member 26 areopen to the atmosphere through vent 40, while the pressure of compressedair from chamber 38 is imposed upon the opposite side of the diskthrough conduits 39 and passages 37. In this position of the valve, theair being transmitted through conduit 22 travels the path of leastresistance to pocket 32, that is, it flows from passages 3-3 throughpassages 36a to passages 36 and thereafter through conduits 39 intochamber 38. The pressure of the air entering chamher 38 forces hammer 17back along bore 28 of the barrel into cocked position adjacent valvehousing member 26. As the hammer is cooked, the air trapped in thebarrel ahead of it is partially vented through vent 40 until the hammerpasses the vent and valves it oflF. Thereafter the remaining air trappedin the barrel by the hammer is compressed to absorb the impact of thecocking hammer. Simultaneously with the air being compressed at thevalve side of the hammer, the pressure at the opposite side thereof isreduced by the escape of air through vents 40 and 41, the result of thisbeing to slow down the movement of the hammer and reverse the pressuredifferential across the valve disk so that it is shifted in pocket 32 toopen communication between passages 33 and conduit 22 and bore 28 of thebarrel.

At this point in the operation of air hammer it), with directcommunication established between the source of air and the bore ofbarrel 16, the air will alter its course to follow the new path of leastresistance and flow through passages 33 and bore 35 into the barrel. Theforce of the air striking the rear face of hammer 17 will drive thehammer toward the opposite end of barrel 16, into tool contactingposition, with sufficient force to operate tool 19. As the hammertravels the length of the barrel, the air ahead of it is expelledthrough vents 40 and 41 so as not to adversely affect its movement. Whenthe hammer has passed vent 49, some of the driving pressure behind it isrelieved through that vent to initially slow the hammer and prepare forthe subsequent cocking operation, as was previously described. Continuedmovement of the hammer toward tool contacting position causes vent 41 tobe valved-off so that a quantity of air is trapped in the barrel andcompressed in chamber 38 for absorbing the impact of the driving hammer.It will be understood that the hammer is again in driving or toolcontacting positon, as it was when its operation was begun, and that thepressure ditferential across valve disk 24 is again reversed forrecocking of the hammer.

A feature of the invention which should at this time be noted, is theutilization of the air vented from barrel 16 through vents 40 and 41during the reciprocation of the hammer for cooling tool 19 and blowingdust or similar particles away from the point of the tool. The air whichis expelled through the vents is guided between the hood 42 and theouter surface of barrel 16 to a port or orifice 43 adjacent toolmounting means 13 from which it is discharged in the direction of theworking end of tool 19.

By means of the sequentially operated valve assembly 12,above-described, which is actuated in response to the position of thereciprocable hammer within the barrel, a fluid operated hand tool isprovided which is automatic and reliable and positive in operation whichbeing relatively simple in structure.

In order to further facilitate the operation of air harnmer 10 and toenable the rapidity of the hammer stroke and the force of the blow to beregulated, an adjustable trigger assembly 23 is provided for controllingthe flow of fluid through conduit 22 to valve assembly 12. While it isconventional practice to utilize trigger assemblies or the like foropening and closing communication b tween a fluid-operated hammer and asource of fluid under pressure, in the instant invention it iscontemplated that a trigger assembly will be utilized which, in additionto stopping and starting the hammer, will regulate the quantity of fluidflowing to the valve assembly.

According to the invention, the trigger assembly comprises a triggermounting portion 44 adapted to be threaded into a bore in pistol grip 13of hammer housing 11 for dissecting conduit 22. The mounting portion 44is formed with a bore 45 having an enlarged portion 46 at its inner endproviding an air pocket and an enlarged threaded outer bore portion 47adapted to adjustably receive a threaded bushing 48. A lateral passage46a is provided in mounting portion 44 opening into air pocket 46 andcommunicating the same with one side of conduit 22. The bushing 48 isformed with an axially extending bore 49 in alignment with, and of equaldiameter with the bore 45 of the mounting portion and is provided withan enlarged head 50 outwardly of the mounting portion. The inner end ofthe bushing is provided with an integral nose portion 51 of reduceddiameter relative to the enlarged bore 47 of the mounting portion havinga plurality of elongate teeth 51a extending parallel to the axis of thebushing. A valve 52 having a valve head 52a and a valve stem 53 providedwith an enlarged head 54 is mounted by trigger mounting portion 44 withthe valve stem slidably carried in the bore 49 of the bushing 48 and thebore 45 of the mounting portion. Resilient means 55 in the form of acoil spring or the like positioned Within conduit 22 of hammer housing-11 bear on valve head 52a for normally biasing valve stem 53 outwardlyof bushing 48 so that the valve head closes off air pocket 46 tosealingly divide conduit 22. When trigger assembly 23 is operated toopen valve 52 and communicate separate portions of conduit 22, valvestem 53 is shifted inwardly of bushing 48 against spring 55 to move thevalve head 52a so that air may flow through air pocket 46 and passage46a. The engagement of enlarged head 54 of the valve stem with theenlarged head 50 of the bushing limits the inward movement of the valvestem, thereby controlling the amount the valve is opened with aresultant control of the amount of air which is permitted to flowthrough conduit 22.

Adjustment of the trigger assembly 23 is achieved by threading bushing48 into or out of mounting portion 44 a greater or lesser distance,thereby increasing or decreasing the length of the stroke of valve stem53 and the separation between valve head 52a and the open end of the airpocket 46 in the mounting portion 44. In order to lock bushing 48 inadjusted position Within the enlarged threaded bore portion 47 ofmounting portion 44, resilient means are connected to the mountingportion for resiliently engaging the elongate teeth 51a of the bushingto prevent inadvertent movement between the bushing and the mountingportion. It is contemplated that the resilient means will comprise asubstantially C-shaped spring element 56 having a flat arm or grippingportion 57 provided with a detent 53. An annular groove 59 formed in themounting portion 44 and provided with a flat 60 is adapted to receivethe spring element, with the arm 57 engaging the flat, so that theelement is retained against movement relative to the mounting portionand the detent 58 engages the teeth 51a of the bushing. By means of theresilient locking means, adjustments of the trigger assembly arepositively maintained during the operation of the air hammer, yetreadjustment of the assembly may be accomplished Without resort to toolsor complicated and difiicult manipulation of the parts.

Referring now to FIGS. 1 and 8 of the drawings, the tool mountingassembly 18 of the invention is shown. Heretofore, the problem has beenencountered of mounting an impact tool or the like in operative positionin a fluid-operated hammer so that it cannot be accidently dischargedtherefrom when the hammer is operated and the tool is not in engagementwith a workpiece. Prior attempts to solve this problem have required theredesign of the tools or have involved structures which complicate themounting and removal of the tool from the fluid-operated hammer.According to the present invention, the tool mounting assembly isadapted to support the tool in axial alignment with the reciprocatinghammer so that it is normally biased away from hammer contactingposition, whereby the air hammer may idle, when the tool is not engagedwith a workpiece, without danger of the tool being shot from its mountby the impact of the hammer thereon. The instant tool mounting assemblyis adapted to facilitate the shifting of the tool into hammer contactingposition to enable it to be operated thereby. The retaining means forgripping the tool in mounted position are resilient in nature, therebyfacilitating the ready mounting and removal of the tool from the airhammer.

The tool mounting assembly 18 comprises a sleeve or chuck 61 having abore 62 therein adapted to slidably receive the shank of tool 19. Thechuck is threaded into an enlarged bore 63 in the end of the barreldirected away from valve assembly 12 and is in alignment with the bore28 of the barrel in which hammer 17 reciprocates. Inwardly of barrel 16,between enlarged bore 63' and hammer bore 28, is a bore 64 of reduceddiameter openly communicating with the bores 28 and 63. The bore 64 isadapted to house a resilient member 65 in the form of a coil spring orthe like which in turn is adapted to removably telescopically receivethe tool contacting nose 17a of the hammer 17. An annular washer 66,having an external diameter slightly larger than the bore 62 of sleeve61 and an internal diameter slightly smaller than the tool 19, isslidably positioned within bore 64 to be engaged by spring 65. Thewasher, which is adapted to telescopically receive the bevelled tip 17bof nose 17a of the hammer when spring 65 is compressed and the hammer isin driving position, is normally biased by the spring into engagementwith the end of tool supportiing sleeve 61. The sleeve is formedintermediate its length with a peripheral groove 67 having a pluralityof bores 68 extending radially therefrom into tool receiving bore 62 ofthe sleeve. The bores 68, which are shouldered at their inner ends as at69, are adapted to slidably receive ball bearings 70 for engaging theshank of the tool 19 when it is inserted in the mounting assembly. Aresilient ring or clamp 71 is positioned in groove 67 for normallybiasing balls 70 into bore 62 of the sleeve. It will be understood thatwhile the tool 19 may be merely inserted in sleeve 62 and frictionallygripped by the balls therein, in the illustrated form of the inventionthe tool is shown as being provided with notches 72 for slidablyreceiving the balls.

In the operation of tool mounting assembly 18', the tool 19 is normallybiased outwardly of sleeve 61 by spring 65 acting through washer 66 onits anvil end as shown in FIG. 1. In this position of tool 19 the airhammer may be operated without the hammer 17 striking the tool with theresultant danger of the tool being shot from its support. On the forwardor driving stroke of hammer 17 the nose portion 17a thereof merelypasses through coil spring 65 without contacting the tool 19. When it isdesired to operate the tool it is only necessary to place the tipthereof against a workpiece with suflicient pressure to compress spring65 so that the tool enters bore 64 and is in hammer contacting position,as shown in FIG. 8.

. On the forward stroke of hammer 17, in this position of tool 19, thenose 17a of the hammer passes through spring and the end of the bevelledtip 17b passes through washer 66 and strikes the anvil of the tool todrive it forward. By means of the tool mounting assembly, hereinabove-described, a cutting tool or the like may be readily mounted andremoved from a fluid-operated hammer and is normally supported thereinout of hammer contacting position so that the air hammer may be idledWithout danger.

Thus, among others, the several objects and advantages of the inventionas aforenoted are achieved. Obviously, numerous changes in the structuremay be resorted to without departing from the spirit of the invention asdefined by the claims.

I claim:

1. A fluid-operated hammer comprising a housing having a valve assemblymounted therein, means for connecting said housing to a source of fluidunder pressure and transmitting the fluid to said valve assembly,trigger assembly means mounted by said housing for controlling the flowof said fluid under pressure to said valve assembly, a barrel having areciprocable hammer therein forming part of said housing, said hammerbeing reciprocated by said fluid in response to the operation of saidvalve assembly, means responsive to the position of said hammer in saidbarrel for sequentially operating said valve assembly to reciprocatesaid hammer, means mounting a tool on the housing for direct impact bysaid hammer, said means providing for sliding movement of the toolbetween a hammer contacting and an idle position, and means cooperatingbetween said barrel and said hammer for forming an air trap cushioningthe impact of said reciprocating hammer.

2. A fluid-operated hammer comprising a housing having a valve assemblymounted therein, means for connecting said housing to a source of fluidunder pressure and transmitting the fluid to said valve assembly,trigger assembly means mounted by said housing for controlling the flowof said fluid under pressure to said valve assembly, a barrel having areciprocable hammer therein connected to said housing, said hammer beingreciprocated by said fluid in response to the operation of said valveassembly, said valve assembly including a movable valve disk adapted tobe shifted between hammer driving and cocked positions, vent means insaid barrel for relieving the pressure therein as said hammer isreciprocated, means for sequentially shifting said valve disk foroperating said valve assembly to reciprocate said hammer, said shiftingmeans including means for creating a pressure differential between theopposite sides of said disk so that the fluid is enabled to enter saidbarrel and drive said hammer and reversing the pressure diflerential toshift the disk so that the fiuid enters said barrel to cock said hammer,means mounting a tool on the housing for direct impact by said hammer,said means providing for sliding movement of the tool between a hammercontacting and an idle position, and means cooperating between saidbarrel and said hammer for closing said vent means so that fluid istrapped in said barrel ahead of said hammer for cushioning the impact ofsaid reciprocating hammer.

3. A fluid-operated hammer as in claim 2, wherein said means forsequentially creating a pressure diflerential between opposite sides ofsaid disk and reversing the same for shifting said disk comprises meansfor creating a pressure differential at opposite sides of said hammerand sequentially reversing the same, said means including said ventmeans and means for transmitting the fluid trapped in said barrel aheadof said hammer in tool contacting position to said disk.

4. A fluid-operated hammer comprising a housing having a valve assemblymounted therein, means for connecting said housing to a source of fluidunder pressure and transmitting the fluid to said valve assembly,trigger assembly means mounted by said housing for controlling the flowof said fluid under pressure to said valve assembly, a barrel having areciprocable hammer therein connected to said housing, said hammer beingreciprocated by said fluid in response to the operation of said valveassembly, means responsive to the position of said hammer in said barrelfor sequentially operating said valve assembly to reciprocate saidhammer, vent means for relieving the pressure in said barrel ahead ofsaid hammer as the latter reciprocates, means connected to said barrelfor mounting a tool adapted to be shifted between hammer contacting andidle position, hood means connected to said barrel and enclosing saidvent means for controlling the flow of fluid vented thereby anddirecting it ahead of said tool, and means cooperating between saidbarrel and said hammer for trapping air and cushioning the impact ofsaid reciprocating hammer.

5. An adjustable trigger assembly for use in regulating and controllinga flow of fluid to a valve assembly in a fluid-operated hammer having ahousing comprising a trigger mounting portion connected to said housing,a valve having a valve stem, said stern being movably mounted by saidmounting portion and being adapted to open and close said valve onmovement thereof, means for adjustably limiting the movement of saidvalve stem in valve opening direction so that the trigger assembly isregulated and resilient spring means for locking said limiting means inadjusted position.

6. An adjustable trigger assembly for use in regulating and controllinga flow of fluid to a valve assembly in a fluid-operated hammer having ahousing comprising a trigger mounting portion connected to said housing,a bushing having an enlarged tflange movably mounted by said mountingportion for adjustment toward and away from said housing, a valve havinga valve stem provided with an enlarged head, said stem being movablymounted by said bushing and being adapted to open and close said valveon movement thereof, said head engaging said flange on said bushing forlimiting the movement of said stem in valve opening direction andresilient spring means for locking said bushing in adjusted positionrelative to said mounting portion.

7. An adjustable trigger assembly for use in regulating and controllinga flow of fluid to a valve assembly in a fluid-operated hammer having ahousing comprising a trigger mounting portion having a threaded boretherethrough connected to said housing, a bushing adjustably threadedlyconnected within the bore of said mounting portion for adjustment towardand away from said housing, said bushing having an enlarged headoutwardly of said mounting portion and a nose portion of reduceddiameter relative to the bore of said mounting portion provided withelongate serrations extending parallel to the axis of said bushing, avalve having a valve stem provided with an enlarged head, said stembeing movably mounted by said bushing and being adapted to open andclose said valve upon the movement thereof, said head engaging saidenlarged head on said bushing for limiting the movement of said stem invalve opening direction and a resilient spring element secured to saidmounting portion against movement relative thereto and resilientlyengaging said serrated nose portion for locking said bushing in adjustedposition relative to the mounting portion.

8. In a fluid-operated hammer including a housing having a valve meansmounted therein, means for connecting said housing to a source of fluidunder pressure and transmitting the fluid to said valve means, meansmounted by the housing for controlling the flow of said fluid to saidvalve means, a barrel having a reciprocable hammer therein connected tosaid housing, said hammer being reciprocated by said fluid in responseto the operation of said valve means, means for operating said valvemeans to reciprocate said hammer and means connected to said barrel formounting a tool; the improvement wherein said tool mounting meansincludes resilient means comprising a coiled spring positioned in arecess between the barrel and the tool mounting means and aligned withthe hammer to receive the same, an abutment means engaging the end ofthe spring adjacent the tool to engage the tool and yieldably bias thetool to an idle position, said abutment means having an aperture throughwhich the hammer passes when the spring is compressed and the tool ismoved in the tool mounting means from idle to tool contacting positionto be directly engaged thereby.

9. In a fluid-operated hammer including a housing having a valve meansmounted therein, means for connecting said housing to a source of fluidunder pressure and transmitting the fluid to said valve means, meansmounted by the housing for controlling the flow of said fluid to saidvalve means, a barrel having a reciprocable hammer therein connected tosaid housing, said hammer being reciprocated by said fluid in responseto the operation of said valve means, means for operating said valvemeans to reciprocate said hammer and means connected to said barrel formounting a tool; the improvement wherein said tool mounting meansremovably mounts said tool and resiliently biases said tool away fromhammer contacting position, said tool mounting means comprising a sleevehaving a bore adapted to slidably receive and support a tool inalignment with said hammer, said sleeve being connected to said barreland cooperating therewith to form a recess to house resilient means fornormally engaging the end of the tool and shifting said tool away fromhammer contacting position and resilient means carried by said sleevefor slidably retaining said tool therein.

10. In a fluid-operated hammer including a housing 10 having a valveassembly mounted therein, means for connecting said housing to a sourceof fluid under pressure and transmitting the fluid to said valveassembly, means mounted by the housing for controlling the flow of saidfluid to said valve assembly, a barrel having a reciprocable hammertherein connected to said housing, said hammer being reciprocated bysaid fluid in response to the operation of said valve assembly, meansfor operating said valve assembly to reciprocate said hammer and meansconnected to said barrel for mounting a tool; the improvement whereinsaid tool mounting means removably mounts said tool for directengagement by the hammer and resiliently biases said tool away fromhammer contacting position, said tool mounting means comprising a sleevehaving a bore adapted to slidably receive and support the tool inalignment with said hammer, said sleeve being connected to said barreland cooperating therewith to form a recess to house a coil springadapted to telescopically receive an end of said hammer and having meansto engage an end of said tool for normally biasing the latter away fromsaid hammer, said lastnamed means having an aperture therein throughwhich said hammer passes into said direct engagement with the tool whenthe tool is moved to compress said spring and ball bearing meansresiliently mounted in said sleeve and projecting into said bore formovably engaging said tool and retaining it in mounted position.

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1. A FLUID-OPERATED HAMMER COMPRISING A HOUSING HAVING A VALVE ASSEMBLYMOUNTED THEREIN, MEANS FOR CONNECTING SAID HOUSING TO A SOURCE OF FLUIDUNDER PRESSURE AND TRANSMITTING THE FLUID TO SAID VALVE ASSEMBLY,TRIGGER ASSEMBLY MEANS MOUNTED BY SAID HOUSING FOR CONTROLLING THE FLOWOF SAID FLUID UNDER PRESSURE TO SAID VALVE ASSEMBLY, A BARREL HAVING ARECIPROCABLE HAMMER THEREIN FORMING PART OF SAID HOUSING, SAID HAMMERBEING RECIPROCATED BY SAID FLUID IN RESPONSE TO THE OPERATION OF SAIDVALVE ASSEMBLY, MEANS RESPONSIVE TO THE POSITION OF SAID HAMMER IN SAIDBARREL FOR SEQUENTIALLY OPERATING SAID VALVE ASSEMBLY TO RECIPROCATESAID HAMMER, MEANS MOUNTING A TOOL ON THE HOUSING FOR DIRECT IMPACT BYSAID HAMMER, SAID MEANS PROVIDING FOR SLIDING MOVEMENT OF THE TOOLBETWEEN A HAMMER CONTACTING AND AN IDLE POSITION, AND MEANS COOPERATINGBETWEEN SAID BARREL AND SAID HAMMER FOR FORMING AN AIR TRAP CUSHIONINGTHE IMPACT OF SAID RECIPROCATING HAMMER.